Are you wanting to know how long diazepam is working in your system or how long it takes for it to not be detected in a urine drug screen? Kaismama is right in saying how long diazepam can work in the system (or be active in the bloodstream) BUT diazepam and its metabolites can be detected in urine up to 30 days after the last dose is taken. Benzodiazepines store in the fat so they can take a long time to completely metabolize and exit the body.

Hello Debbie Ellis. Valium/Diazepam (long acting/lasting benzodiazepine) will take 1 to 2 hours to begin to work. Age is factor in the drugs half life. Meaning the older the person taking the drug, be it one pill or five pills and the dose per pill will take longer to eliminate from your/ones system. It will take a person from 20 to 100 hours to get the drug out of your system. Detection is another formula. Liver, age will play a role. Regards pledge